Wow, there are so many options.
I'd have to go with:
Chris Benoit vs. Samoe Joe vs. Kurt Angle, simply because of the free wrestling clinic these guys would create.
Undertaker vs. Kane, those two guys always get the blood pumping.
Triple H vs. Randy Orton vs. Edge vs. HBK (No tag-team alliance) - 2 of the most credited superstars ever in WWE, possibly the best heel of all time, and the future of WWE, how can anything go wrong?
Booker vs. Finlay, would create a good solid, upper mid-card feud, with the winner elevating to main-event status again.
Batista vs. RVD, though it may sound odd, these two's styles would clash and possibly create something good.
Cena vs. Benjamin vs. Nitro, as Benjamin is a fantastic athlete, Nitro is developing quickly, and when Cena is allowed to wrestle naturally, and forget about playing with the crowd a lot, he is a decent wrestler, and could provide a power element to the Intercontinental Title mix.
The Hooliganz vs. Cryme Tyme vs. The Hardyz, three teams with nice styles, and could put on some great spots, with highflying going on everywhere.
Rey Mysterio vs. Jimmy Wang Yang vs. Gregory Helms, firstly, because these three are the people that will bring respectability back to the cruiserweight division, and secondly, to stop this nonsense with Chavo and Rey, and quit making money out of Eddie's name. Respect the man, damnit. Viva La Raza.
NOTE: These are not fantasy picks, I am using currently used wrestlers of the WWE.